Climate-adaptive anti-ageing design for asphalt using hindered-amine-intercalated zirconium phosphate

The effectiveness of asphalt anti-ageing agents is strongly climate-dependent, yet their design is rarely tailored to specific service environments. This study proposes a climate-informed method for designing asphalt anti-ageing systems for plateau regions, using Lhasa, China, as a representative case. Ageing a 1 mm asphalt film for 150 h at 1027 W/m², 87.6 °C, and 36% relative humidity was found to simulate approximately 15 years of field ageing in Lhasa. Three anti-ageing systems were developed using a hindered amine light stabiliser (OT), hindered amine antioxidant-intercalated zirconium phosphate (IZ), and hindered amine light stabiliser-intercalated zirconium phosphate (TZ). Weighted optimisation identified P1 (1% OT), P2 (2% OT + 4% IZ), and P3 (1.5% OT + 3% TZ) as the preferred formulations. All systems improved low-temperature performance and fatigue resistance of aslhalt. Organic anti-ageing efficacy declined with ageing time, whereas the composite systems showed superior and more stable long-term performance due to the synergistic barrier effect of zirconium phosphate and radical-stabilisation of hindered amines. P3 provided the best balance of pavement performance, long-term durability, and cost, extending predicted service life by 125.33%. The proposed method provides a practical framework for climate-adapted asphalt anti-ageing design.